In a typical controller-based wireless local area network (WLAN), all access points (APs) are connected to the WLAN Controller (the WLAN manager) by wire. It is therefore relatively straightforward to upgrade software for the APs or to upgrade the configuration of APs. For example, with wireless access points that are lightweight access points whose AP functionality is controlled by a controller, all lightweight access point software images are embedded in the Controller image. When a controller image is upgraded, each time an AP joins that controller, a version check is carried out, and if needed, the controller upgrades the access point.
In a wireless mesh network, on the other hand, the mesh points that are access points, called mesh access points (mesh APs) are typically wirelessly connected in a hierarchical tree topology, that is, there is a parent-child relationship between almost all of the mesh APs up to the root of the tree topology, which is the mesh AP called a root AP or root mesh AP. Such a root AP typically includes a wired link to a wired network. Any software upgrade or any configuration change such as a change in data-rate, change of channel, change of power, change of range and so forth, flows in a multi-step top-down manner outward from the root AP, making several parent-child hops, even though to the WLAN manager, the change request(s) appear as if they occur in parallel. As a result, when a particular mesh AP is being upgraded or configured, there is in effect an outage of the segment of the mesh network below the particular mesh AP being upgraded in the tree topology. This is of course undesirable. Such upgrades may cause chaotic network outages lasting an unpredictable period of time, typically between several minutes and several hours.